Hi slick, thanks for your help.
We took your advice and sent a recorded delivery letter stating that we were only willing to pay a further one months membership to cover the month following cancellation of my son's direct debit .
We refused to pay their additional charges quoting the precious judgement in previous threads on this site .
We have had a letter from them still insisting on payment within 7 days .
They also refute our point that their charges are unenforceable and state that each case has different costs ,which to me seems a veiled threat that if we don't settle costs will increase .
Any advice on how to proceed ?